Power system analysis, electric power transmission and energy storage

Research and development in power system issues will be an important part of the ongoing energy transition. Our power system is facing a series of changes and its function will play a key role in creating a sustainable society.

The division of Electricity works with a number of different research projects that in many cases take place in close collaboration with industry, society and other actors. Our ambition is to educate doctoral students who can contribute with cutting-edge competence in a defined area and at the same time have good overall electrical system knowledge.

Power system analysis

The role of the inverter in the electrical system

In this project, we wanted to investigate the role of the inverter in the electricity system and how the stability of the system is affected when more and more production is controlled with power electronics. Various converters and their functions were studied in detail and the aim was to also study microgrids. This is a doctoral project funded by SweGRIDS with Vattenfall as its industrial partner.

Need for energy storage in the future distribution system to ensure stable operation and good power quality.

Increasing urbanization and increased electricity use means that the need for electricity in some places can be expected to be large and expansions of the electricity grid can sometimes not take place at the pace that would be desirable. An alternative to a power system expansion could be the installation of a local energy storage. In this project, we aim to study the need for energy storage in the distribution network and what functions that energy storage can fulfill. The study also includes studying various flexibility solutions.

Electric energy storage

Electric energy storage and control systems are needed to stabilize electric grids with a large proportion of renewable energy sources. Modern flywheels provide a method for storing electric energy in applications where long time storage is not needed, such as buffering energy in electric cars.

The Kinetic Energy Storage System (KESS) has been found a promising solution for facilitating the introduction of electric vehicles and/or integration of intermittent sources of electric energy in the grid. Our research takes advantage of recent development in the fields of magnetic bearings, electric machine design and composite material. Main research topics include:

Magnetic bearings: Complex systems, relying on high-speed control and power electronics, showing great potential for decreasing losses in high-speed rotating systems.
Electric machine design: The topology and function has large impact on the main properties of the KESS.
Electric driveline: Using kinetic energy storage systems in combination with traditional battery storage opens up new and exciting ways of optimizing the electric propulsion system
Carbon- and/or glass-fiber composites: These material have the potential to greatly increase specific energy of the KESS, thanks to high tensile strength and low density.

The group do both theoretical and experimental work. Several prototypes have been constructed over recent years showing the benefits of:

Different topologies of electric machines, including PMSM and axial flux reluctance machines.
Reduction of losses from magnetic bearings.
A complete novel electric driveline
Rotors constructed from mixed glass- and carbon fiber composite material.

For more information on electric energy storage, please contact Hans Bernhoff: hans.bernhoff@angstrom.uu.se

Smart charging on local level

In the green transition, research is needed that secures tomorrow's energy supply. As the proportion of electric cars increases and the need to switch to fossil-free fuels grows, we must find solutions to reduce the risks of capacity shortages in the electricity grid. At the Division of Electricity, new technologies and systems are being researched to enable electric car charging in large capacity while relieving the electricity grid.

Dansmästaren is the largest parking facility in Uppsala and simultaneously functions as a test bed for developing, test-running and evaluating algorithms for load calculation and smart charging. The facility has been equipped with a large solar cell park and an advanced battery facility that allows for the storage of self-produced electricity that can be used to relieve the power grid when several cars are being charged at the same time.

The research project, which is a collaboration with Uppsala Parkerings AB, results in many lessons learned about smart energy system management that will also be implemented in the company's current and future facilities. The hope is also that the developed solutions can be exported to other countries and strengthen Swedish innovative industry.

See a YouTube-video about the project (in Swedish)